Steering arranagement for ships with water jet unit

ABSTRACT

The present invention relates to a steering arrangement for ships with water jet unit, comprising a steering device that is pivotable about an essentially vertical shaft having a first centre line, at least one hydraulic cylinder articulately connected at a first end of the hydraulic cylinder to the attachment flange of the water jet unit, a turning device connected to said shaft for attachment to a second end of said hydraulic cylinder at a distance from said shaft, a reversing device for pivoting the steering device, the reversing device being arranged about an essentially horizontal shaft, an additional hydraulic cylinder arranged to act on the reversing device, the additional hydraulic cylinder following the movement of the steering device, characterized in that all the hydraulic cylinders are arranged within a sheltered space located above the extension of said vertical shaft.

TECHNICAL FIELD

[0001] The present invention relates to a steering arrangement for shipswith water jet unit, comprising a steering device that is pivotableabout an essentially vertical shaft having a first centre line, at leastone hydraulic cylinder articulately connected at a first end of thehydraulic cylinder to the attachment flange of the water jet unit, aturning device connected to said shaft for attachment to a second end ofsaid hydraulic cylinder at a distance from said shaft for pivoting thesteering device, a reversing device being arranged about an essentiallyhorizontal shaft, an additional hydraulic cylinder arranged to act onthe reversing device, the additional hydraulic cylinder following themovement of the steering device.

STATE OF THE ART AND PROBLEM

[0002] Large water jet units have lately become more and more popularfor driving bigger ships. Steering a ship with water jet is achievedaccording to a well-known principle by means of a box-shaped, pivotingsteering device controlled by powerful hydraulic cylinder units, and areversing device controlled by its own hydraulic cylinder and suspendedin the steering device. However, the hydraulics is placed in the water,that is, outside the body. This involves a potential environmentalhazard since the conduits with hydraulic oil for the cylinders mightbreak and cause leakage of hydraulic oil into the water. It is a wishfrom some clients that this potential safety hazard is eliminated.

[0003] It is known to solve said problem by moving the hydraulic pistonsinside the craft's transom frame and instead control the steering deviceand the reversing device suspended in the steering device by means oflinked mechanisms, which are described in “Speed at Sea” in theJune-number 2000. Because of the location of the reversing device theselinked mechanisms are very long and cumbrous. It also causes unwantedextra penetration of the transom, which has to be sealed. Sincemovements are desired in both the vertical and the horizontal directionthis solution also leads to several hinges, which may cause problemsconcerning both structural strength and accuracy of steering.

[0004] An alternative solution to this problem is disclosed in U.S. Pat.No. 3,422,788, where it is chosen not to make the whole steering devicepivoted but only a rudder-like element placed inside a kind of steeringdevice, which is fixed. The reversing device is, in its part, suspendedin the fixed steering device. Thus, the problem of the reversingdevice's influence is solved since the hydraulic piston that acts on thereversing device does not have to participate in any lateral movements.However, this solution involves many other considerable disadvantages,above all, an essentially deteriorated efficiency. Hence, it is not anacceptable solution.

[0005] Also through U.S. Pat. No. 3,807,346 a water jet is previouslyknown where the steering- and reversing devices are controlled by ahydraulic placed in a sheltered position. However, this solution showsthat the reversing device moves laterally, not vertically, which is theconventional and desirable solution. Hence, this alternativeconstruction is not desirable.

BRIEF DESCRIPTION OF THE INVENTION

[0006] It is an object of the present invention to find an optimalsolution to the above-described complex of problems. This is achieved bymeans of a steering arrangement for ships with water jet unit,comprising a steering device that is pivotable about an essentiallyvertical shaft having a first centre line, at least one hydrauliccylinder articulately connected at a first end of the hydraulic cylinderto the attachment flange of the water jet unit, a turning deviceconnected to said shaft for attachment to a second end of said hydrauliccylinder at a distance from said shaft for pivoting the steering device,a reversing device being arranged around an essentially horizontalshaft, an additional hydraulic cylinder arranged to act on the reversingdevice, the additional hydraulic cylinder following the movement of thesteering device, wherein all hydraulic cylinders are arranged within asheltered space located above the extension of said vertical shaft, andsaid sheltered space at the rear end is arranged with a slit shapedopening.

[0007] Due to this solution it is possible to achieve a shelteredinclusion of hydraulic conduits and connections, and also a shelteredlocation of possible positional measuring equipment for automaticcontrol of the steering, simultaneously avoiding unwanted linkagemechanisms.

[0008] According to further aspects of the invention:

[0009] said hydraulic cylinder to act on the reversing device ispivotally suspended about an essentially horizontal shaft having asecond centre line,

[0010] said centre line for said hydraulic cylinder comes close to,preferably cuts, said first centre line,

[0011] said second centre line for the suspension of the hydrauliccylinder comes close to, preferably cuts, said first centre line,

[0012] said space is shaped as a module,

[0013] also said positional measuring equipment for measuring theposition of the steering device and/or the reversing device is arrangedwithin said space,

[0014] said bottom-part of said space is at least partially arrangedabove and in contact with the outlet-part of the water jet unit,

[0015] two cylinders are used for turning said steering device, whichare articulately connected to the turning device with one of their endsat both sides of said shaft,

[0016] said sheltered space at the rear end is arranged with a sealed,preferably slit-shaped opening for the piston rod for the reversingdevice, that said piston rod in an sealed manner may move forwards andbackwards and possibly also vertically,

[0017] said upper end of said shaft is placed within said space.

DESCRIPTION OF DRAWINGS

[0018] The invention will be explained more in detail with reference tothe attached drawings, wherein

[0019]FIG. 1 shows a preferred steering arrangement according to theinvention as a side view, partly as a cross-section,

[0020]FIG. 2 shows the same view as FIG. 1 but with the reversing devicein another position,

[0021]FIG. 3 shows the steering arrangement according to FIG. 1 seenfrom above, partly as a cross-section,

[0022]FIG. 4 shows the same view as FIG. 3 but with the steering devicein another position, and

[0023]FIG. 5 shows a side view of a modified arrangement to according tothe invention.

DETAILED DESCRIPTION OF THE INVENTION

[0024] In FIGS. 1 and 2 there is shown in a side view two differentpositions for an arrangement according to the invention. The basicdesign of the steering arrangement is made in a conventional way. Thus,a steering arrangement known in itself is disclosed that comprises asteering device 6 that is pivotable about a vertical shaft 5, which isfixed in the water jet's outlet-part 20 which in its turn is attached tothe ship's transom. Furthermore, this basic construction consists of abeam arrangement fixed at each side of the steering device and in whichthere is arranged a hinge 12 for suspension of a lever arm 17 of areversing device 7. In FIG. 1 the reversing device is shown in itsinactivated mode, that is, a position for full speed ahead.

[0025] In FIG. 2 the reversing device is shown in an activated mode,where the jet stream thus is diverted for the achievement of a reversingforce.

[0026] The novel feature of this design is the arrangement of thehydraulic cylinders 2, 3, 9 that act on steering device 6, and reversingdevice 7 respectively. The cylinders 2, 3, 9 are arranged within aclosed space 1 above the basic construction. The space is box-shaped anddelimited by a number of plates 1A-1G. The front plate 1E is meant to befixed to the jet unit's attachment flange 11, while the rear plate 1G isarranged at a sufficient distance from the front plate 1E to be able tohold the whole cylinder 9 (for the reversing device 7) which is placedfurthest back of the cylinders 2, 3, 9 which are about the same size.The lower plate 1F is partly arranged essentially horizontally and holdsthe upper end of the vertical shaft 5 for the steering device 6. Theupper plates 1A, 1B are arranged so that sufficient space is obtainedfor hydraulic cylinders with associated surrounding equipment, i.ahydraulic conduits and positional measuring equipment. A yoke-shapedswinging arm 4 is fixed at and pivotable together with the verticalshaft 5. Two shaft pivots 14A, 14B (see FIG. 3) are arranged on top ofthis swinging arm 4, and the front end 3A, 2A of the hydraulic cylinders2,3 for turning the steering device 6 are articulately arranged at saidshaft pivots. Moreover, there is at said swinging arm 4 arranged twoattachment handles 15 for pivotable suspension of the hydraulic cylinder9 by a shaft 13 that is fixed at said hydraulic cylinder 9. Thus, thehydraulic cylinder 9 for the reversing device 7 is connected to theshaft 5 so that it swings along with it in its movements. The centreline C2 of the shaft 13 for suspension of the cylinder 9 is arrangedsuch that it crosses the centre line C1 of the vertical shaft 5.Moreover, the centre line C3 for the hydraulic cylinder 9, (se FIG. 4)is arranged to cross the centre line C1 of the vertical shaft 5. Thissuspension means that the relative position of the reversing device 7related to its hydraulic cylinder 9, is not influenced by the steeringdevice's 6 relative position. Thus the reversing device (7) does notchange its position relative to the steering device even if the steeringdevice is turned to different positions, which would be the case if thesuspension of the cylinder 9 were not according to this invention.

[0027] Furthermore, it is shown that the piston rod 9A for acting on thereversing device 7 protrudes from the box-shaped space 1 through asealed slit 16 which is arranged in the back end 1G of thebox-construction. Preferably the slit 16 is sealed to hinder water fromflowing into the sheltered space 1 and also to hinder possibly leakingoil from flowing out from it. The slit 16 enables the hydraulic cylinder9 to perform a pivoting movement about the shaft 13, which is necessarysince the hinge 21 for the piston rod 9A at the linkage arm 17 is movingalong a circular arc, 21A meaning that the hydraulic cylinder 9 must beable to pivot upwards and downwards respectively, when the piston rod 9Ais moving. The respective front end 3A and 2A of the turning hydrauliccylinders 2, 3 are articulately connected about a shaft pivot, that isarranged at the means of attachment element 11A and 1B respectively,which in their turn are firmly attached to the jet unit's attachmentflange 11. Above and in-between said means of attachment elements 11Aand 11B respectively, but within said space 1, a distribution chamber 18for hydraulic oil is arranged, from which the hydraulic conduits 19 forsupply and removal respectively, of oil for the hydraulic cylindersemanates. Due to this arrangement, both distribution chamber 18 andhydraulic conduits 19 will be placed in a sheltered position within saidspace 1.

[0028]FIGS. 3 and 4 show a steering arrangement according to theinvention seen from above. In FIG. 3 the steering arrangement is shownin a swung out position, the steering device 6 being positionedobliquely related to the body's extension to be able to perform a yaw.

[0029] In FIG. 4 the steering device 6 is shown in a folded in position,i.e. for driving straight ahead when the reversing device 7 isinactivated. The position in FIG. 4 is achieved by means of thehydraulic cylinders 2, 3 being positioned with each end 2B, 3B of thepiston rods, in a common plane which is parallel with the jet unit'sattachment flange 11. From this position, by pushing out the piston rodof the lower (in the figure) hydraulic cylinder 3 and at the same timepressing the piston rod of the upper (in the figure) hydraulic cylinder2, the swinging arm 4 is swung about the vertical shaft 5, so that thesteering device 6 is angled relative to the jet unit's attachment flange11 which leads to a yaw.

[0030] Owing to the invention it is gained a sheltered location of thehydraulics without having to use long and cumbrous linkage mechanisms.Also, the module principle, according to the invention entails, thatexisting arrangements can be modified in a simple way, so that shelteredlocation of hydraulics may be installed afterwards.

[0031] In FIG. 5, there is schematically shown a modification accordingto the invention. There is shown in a side view an outlet part 20, andsteering device 6 with substantially the same design as described above.In other aspects the figure shows merely those elements that have beenchanged in relation to the above described preferred embodiment. Animportant difference is that the hydraulic cylinder 9 is fixedlyattached to the attachment device 15A, (which preferably is in the formof a flange) at the top of the vertical shaft 5. The hydraulic cylinder9 is arranged with a corresponding flange 9B, in order to be able tosecurely attach the hydraulic cylinder 9 to the attachment device 15A.Accordingly the piston rod 9A may merely be moved within one and thesame horizontal plane, corresponding with the extension of thecenterline C3 of the piston rod 9A. In order to compensate for themovement along a curve 21A of the hinge 21 for the linkage arm 17 (notshown) there is arranged an intermediate link 17A. This link 17A ispivotally attached to both the arm-hinge 21 at one end and to the pistonhinge 9C at the other end. As described above the hydraulic cylinder(preferably also the other cylinders, which are not shown) is shelteredwithin a substantially closed space 1, having a horizontally extendingslit 16 at one end for the piston rod 9A, such that the rod 9A mayfreely move in/out and sideways. Also in this embodiment the slit 16preferably is sealed. In this connection it is advantageous to nothaving any pivoting movement of the hydraulic piston rod 9A in thevertical plan, i.e. the piston rod 9 will move within the samehorizontal plan in relation to the slit 16 independent of the reversingdevice 7.

[0032] The invention is not limited to what has been described above butmay be varied within the scope of the claims. Thus, it is realized thatit is not necessary with two hydraulic cylinders to act on the swingingarm but that in certain cases it is quite adequate with only onehydraulic cylinder. However, two symmetrically placed hydrauliccylinders for the turning is preferable, not at least forreliability-/safety reasons. Furthermore, it is realized that theprinciple also may be used, by means of linkage mechanisms, to connectin parallel several adjacently arranged steering arrangements.

[0033] The expression “connected to the attachment flange 11 of thewater jet unit” may not be narrowly interpreted, but it is realized that“the connection” may be (and in many cases are) indirect, i.e. theconnection may be formed through one or several intermediate elements.However, it is important the this “connection” is designed so that itmay transmit the forces needed, which in the normal case i.a means thatit is essentially rigid. It is also realized that “the connection” maybe made at the transom stern instead of the jet unit. The main thing isthat “the connection” is made to one of the ships solids. It should beunderstood that the closed space 1 not in all cases need to be sealed,by means of a sealing arrangement in the slit 16. Moreover it should beunderstood that if a seal is used it will not need to totally seal-offthe closed space 1 in all kind of installations. In some installationsit may be sufficient to, hinder a substantial flow of water in and outof the close space 1. Further it should be understood that theexpression slit shaped opening (16) shall be construed in a broadmanner, including alternatives where the opening is half-closed/open bythe use of overlapping, flexible or movable, seal elements that allowthe piston to be moved there between.

1. A steering arrangement for vessels having a water jet unit, thesteering arrangement comprising; a) a steering device (6) that ispivotable about an essentially vertical shaft (5) having a first centreline (C1), b) at least one hydraulic cylinder (2; 3) articulatelyconnected at a first end (2A, 3A) of the hydraulic cylinder to theattachment flange of the water jet unit, c) a turning device (4)connected to said shaft (5) for attachment to a second end (2B; 3B) ofsaid hydraulic cylinder at a distance from said shaft (5) for pivotingthe steering device (6), d) a reversing device (7) being arranged aboutan essentially horizontal shaft (12), e) an additional hydrauliccylinder (9) arranged to act on the reversing device (7), the additionalhydraulic cylinder (9) following the movement of the steering device (6)characterized in that all the hydraulic cylinders (2, 3, 9) are locatedinside a sheltered space (1) located above the extension of the verticalshaft (5) and that said sheltered space (1) at the rear end (1G) isarranged with a slit shaped opening (16).
 2. A steering arrangementaccording to claim 1 characterized in that said hydraulic cylinder (9)arranged to act on the reversing device (7) is pivotally suspended aboutan essentially horizontal shaft (13) having a second centre line (C2).3. Steering arrangement according to claim 2, characterized in that saidcentre line (C3) of said hydraulic cylinder (9) comes close to,preferably crosses, said first centre line (C1).
 4. Steering arrangementaccording to claim 2, characterized in that said second centre line (C2)for the suspension (13) of the hydraulic cylinders (9) comes close to,preferably cuts, said first centre line (C1).
 5. Steering arrangementaccording to claim 1, characterized in that said space (1) is shaped asa module.
 6. Steering arrangement according to claim 1, characterized inthat also positional measuring equipment for measuring the position ofthe steering device (6) and/or the reversing device (7) is arrangedwithin said space.
 7. Steering arrangement according to claim 1,characterized in that said bottom part (1F) of said space (1) at leastfor some part is arranged on top of and in contact with, the outlet part(20) for the water jet unit.
 8. Steering arrangement according to claim1, characterized in that two cylinders (2,3) articulately connected withsaid turning device (4) and with their first ends (2A;3A) on each sideof said shaft (5), are used for turning of the steering device (6). 9.Steering arrangement according to claim 1, characterized in that saidsheltered space (1) at the rear end (11G) is arranged with a sealedopening (16) for the piston rod (9A) for the reversing device (7), sothat said piston rod in a sealed manner may move horisontally within theslit (16) and possibly also vertically.
 10. Steering arrangementaccording to claim 1, characterized in that said upper end of said shaft(5) is placed within said space (1).